The Cambridge Co-processor (National Semiconductor NS32016) User Guide for the BBC Micro
"The Cambridge Co-Processor uses the National Semiconductor 32000 chip set including the NS32016 Central Processor (CPU). Because the C9-Processor is a 32-bit computer, it can perform calculations much more quickly than earlier eight-bit designs, and it can address much more memory; it has an architecture designed for efficient compilation and execution of high-level languages such as Pascal."